Flutter: check if a text string is in a web page?

Let's say I want my flutter app to receive a URL as input, make a connection to the URL, then return a bool indicating whether the word is present in a web page.

Example: let's say https://www.york.ac.uk/teaching/cws/wws/webpage1.html is the input, and the flutter app will return True or False if "EXERCISE" is found in the page.

What packages are helpful to achieve this?